US5417376A - Bone eliminator discharge regulator - Google Patents

Abstract

A device for regulating the discharge of bones and other hard, objectionable material from processed food includes a flow control device contained within a housing applied to the discharge line downstream of a grinding apparatus. The device has a reciprocating valve element having an elongated cylindrical valve head with a groove formed therein at an angle to the longitudinal axis of the valve element. This groove is constantly contacted by the discharge product flow stream in open and closed positions of the valve.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates generally to a bone elimination apparatus, and more specifically, to a means for regulating the discharge of bones and other hard materials from a bone elimination apparatus.

In the food processing industry animal carcasses or remnants are used to produce ground food material. After choice and select portions of the animal are removed from the carcasses, some useable portions of food remain on the carcasses. This useable material may be recovered from the carcasses by subjecting the carcasses to a grinding process. In such processes, the animal carcasses are inserted into a grinding apparatus where the useable food material is processed into a ground form, while the remaining bone and hard tissues are separated and discharged from the grinding apparatus to waste.

Bone elimination devices are well known in the food processing industry. For the most part, these devices are used in association with a grinding apparatus of the type having a tubular grinding chamber with a rotating compression screw or auger extending within the grinding chamber. Food parts, such as carcasses or remnants, are placed into the chamber where the auger contacts and drives the food material through the tube, forming a food material mass in the grinding chamber. The auger may include a series of grinding blades which cut the useable material from the carcasses and may also press it against a perforated portion of the grinding chamber. The auger compresses the food material against the perforations and forces the useable, ground food material out of the grinding chamber through the perforations while retaining the bones and connective tissues in the grinding chamber.

The bones and hard tissue are heavier than the useable soft material of the carcasses so that during the grinding process, this heavier material tends to collect along the auger shaft where it is pushed down the length of the grinding chamber to the end of the grinding chamber. This unusable material is typically discharged through a tube extending out of the meat grinding chamber to a waste collection point. Examples of bone removal equipment having a structure as noted above are fully described in U.S. Pat. Nos. 4,536,920 issued Aug. 27, 1985 and Re. 31,631, issued Jul. 17, 1984.

The equipment described in these two patents utilize an orifice of decreasing size which collects the bones and hard material for discharge and expels them through a discharge opening. Depending on the type of food material being processed, some useable food material may remain on the carcasses or remnants. Other patents describe devices which are suitable for recovering useable food material which still may be attached on the unusable hard portions of the carcasses after a first grinding. Such an apparatus is described in U.S. Pat. No. 5,251,829, issued Oct. 12, 1993 to Weiler and Company of Whitewater, Wis. This patent describes a bone collector assembly in which an additional, or secondary, grinding chamber is located downstream of the primary grinding chamber. This secondary grinding chamber has an additional auger and knife assembly which grinds the hard material discharged from the first grinding chamber a second time, thereby increasing the yield of the useable food material from carcasses.

In using an apparatus of the type described in the above-mentioned '829 patent, it has come to be appreciated that occasionally relatively large amounts of food material are discharged from the grinder apparatus in sporadic spurts as a result of the overall backpressure within the system. When food material is discharged from such a grinding apparatus in large spurts, the backpressure of the system is reduced, and useable food material may be easily ejected out of the grinder along with the unusable material. When large amounts of useable material are discharged in this manner, some food processors may reintroduce the expelled material back into the grinding apparatus for regrinding in an attempt to recover additional useable material. When this reintroduction occurs, the likelihood is increased that some of the hard unusable portions of the food material may be ground into the useable food material, leading to an inferior quality of the ultimate processed food product.

The present invention is therefore directed to a solution to this problem by providing a means to increase the backpressure of the grinding system which regulates the discharge of bones and hard materials from the grinder, thereby substantially eliminating the need to regrind discharged material and reducing the likelihood of reintroducing bone and foreign objects into the processed food material.

In accordance with the present invention, a discharge valve means is provided within the discharge tube of a food grinder which provides control over the flow and backpressure of the grinding apparatus. The valve means is contained within a housing adapted for connection to the discharge opening of a food grinding apparatus. The valve means includes a valve element slidably mounted therein between inlet and outlet openings of the housing. Movement of the valve element occurs along the longitudinal axis of the housing. The valve element includes a valve head or plug for sealing the inlet of the control housing which consequently seals the discharge of the grinding apparatus. The walls of the inlet opening of the control housing serve as the valve seat and cooperate with a multi-surfaced portion of the valve head to regulate a precise flow rate of discharge out of the system so as to remove only rejectable material from the grinder product flow stream.

The multiple surfaces of the valve head serve to increase the overall surface area of the valve head (as compared to a valve element having a constant planar pressure surface profile) in contact with the grinder product flow stream. In a preferred profile, the valve may include a circular groove which extends lengthwise within the valve head at an angle from its axis to define a variable discharge passage in the valve head, such that as the system pressure increases, the valve opening incrementally increases to reduce back pressure on the system so that substantially only rejectable food material is removed from the grinder product flow stream.

Accordingly, it is an object of the present invention to provide a means for regulating the discharge of bones and other hard material from a food material grinder.

It is another object of the present invention to provide a means for increasing the backpressure of a food material grinding apparatus having a bone discharge device which incorporates a flow control means into the bone discharge line of the grinding apparatus which regulates the amount of unusable material discharged from the grinding apparatus, which discharge is regulated solely by the flow of unusable material exiting from the grinding apparatus and not by any external regulation means.

It is still another object of the present invention to provide a means for providing a controlled backpressure on a discharge line of a food material grinding apparatus and thereby regulating the discharge of bones and unusable food material out of the grinding apparatus, wherein the means includes a discharge flow control valve disposed within a bone discharge line, the valve having a valve element which contains a groove of variable size, the size of the groove depending upon the movement of the valve element within the housing in response to the grinding apparatus backpressure, which groove is in contact with the grinding apparatus product flow stream.

Yet another object of the present invention is to provide a bone discharge regulating device for use on a food material grinder having a bone elimination and discharge component, wherein the device is mounted in a discharge line of the bone elimination and discharge component and includes a valve element having a multiple surface profile in contact with the product flow stream, the valve element including a reciprocatable plunger element disposed in the discharge line, the plunger element having a longitudinal groove extending therein, the groove presenting a valve opening which has a specific size at an open position of the valve and which steadily decreases as the valve closes, thereby providing a variable opening within the plunger element which permits bone material to pass through the discharge line through the plunger element groove.

Another object of the present invention is to provide a means for controlling the flow of waste material out of a food grinding apparatus which substantially reduces the overall amount of material discharged to waste from the grinding apparatus while removing substantially all of the bones, hard material and foreign objects from the food material being processed.

These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of this description, reference will be frequently made to the attached drawings in which:

FIG. 1 is a sectional view of the discharge end of a conventional meat grinder having a bone elimination apparatus with a bone discharge tube exiting therefrom which incorporates a bone discharge regulator constructed in accordance with the principles of the present invention;

FIG. 2A is a sectional view of the bone discharge regulator used in the apparatus of FIG. 1, illustrating the regulator in a first, restricted position;

FIG. 2B is a longitudinal sectional view of the bone discharge regulator of FIG. 2A taken along line 2B--2B thereof;

FIG. 3A is a sectional view of the bone discharge regulator of FIG. 1 illustrating the regulator in a second, open position;

FIG. 3B is a longitudinal sectional view of the bone discharge regulator of FIG. 3A taken alongline 3B--3B thereof;

FIG. 4A is a partial sectional view of a valve element used in the bone discharge regulator depicted in FIGS. 1-3;

FIG. 4B is a perspective view of the valve element of FIG. 4A; and,

FIG. 5 is a perspective view of another embodiment of a valve element suitable for use in a bone discharge regulator constructed in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a sectional view of a foodmaterial grinding apparatus 10 having abone removal mechanism 50 upon which the present invention is used. Thegrinding apparatus 10 illustrated in FIG. 1 is a conventional one manufactured by Weiler and Company of Whitewater, Wis. Generally, thegrinder apparatus 10 includes a cylindrical housing 12 having an elongated feed screw orauger 14, extending longitudinally within the housing. The housing 12 forms a primary grindingchamber 15 of the apparatus which contains theauger 14 and arotating knife assembly 16 mounted in the grindingchamber 15. In FIG. 1, for purposes of clarity, certain of the components present above the centerline have been removed to show the placement and passage of the food material mass. These components are symmetrical and have a counterpart half illustrated below the centerline of the grinding apparatus.

Theknife assembly 16 is generally located near the end of the grindingchamber 15 adjacent anorifice plate 18 thereof. Theorifice plate 18 contains two sets ofopenings 19, 20 arranged in a preselected pattern. Openings 19 are relatively small in size and are usually arranged near the outer perimeter of theorifice plate 18. These openings 19 serve as discharge openings or passages for ground, useable food material and may either be open to the environment or, as shown in FIG. 1, to a secondary grinding chamber 17. Theother openings 20 are larger in size than openings 19 and are positioned near the center of theorifice plate 18 around theknife assembly hub 22. Theseopenings 20 serve as passages for useable food material to a second grinding chamber 17 and ultimately, to abone collector cone 24 in the embodiment shown. Theselarger openings 20 may be, for example, generally circular or may, if desired, be of an irregular shape.

Thebone collector cone 24 tapers along its length and terminates in atube portion 26 at its end. Abone discharge auger 28 which is joined to thefeed screw 14 by a suitable connection may extend through thecollector cone 24 and may partially extend into thedischarge tube portion 26. Thebone collector cone 24 may be joined as shown to the secondary grinding chamber 17, or it may be joined to theorifice plate 18 at the end of the first grindingchamber 15. The secondary grinding chamber 17 is defined by acylindrical extension 30 of the main apparatus housing 12. Thisextension 30 is smaller than the grinding apparatus main housing 12 and may contain anadditional knife assembly 32 mounted for rotation on ashaft extension 34.

Anendwall 36 of theextension 30 includes anotherorifice plate 38 similar in configuration to thefirst orifice plate 18 and has two sets of differentlysized openings 39,40. Thefirst openings 39 are small and open to the environment to provide an exit passage for useable food material, while theother openings 40 are large and provide exit passages for bone and other hard and connective tissue.

In operation of the grindingapparatus 10, food parts, such as carcasses or remnants of meat, poultry or fish are fed into a hopper (not shown) of thegrinder apparatus 10. These carcasses typically contain variable amounts of useable food material attached to larger amounts of hard, unusable material such as bone, cartilage, sinew, gristle or the like. Theauger 14 is powered by an electric motor and rotates within the grindingchamber 15 of theapparatus 10. Theauger 14 contacts the carcasses withexterior flights 42. Theauger 14 applies pressure to the carcasses and forms a food material mass 44 which is propelled through the grindingchamber 15 by theauger 14. The pressure within the grindingchamber 15 progressively increases along the length thereof as theauger 14 rotates.

During rotation, the harder material 46 (bones, etc.) will typically settle toward the center of the grindingchamber 15 along the shaft of theauger 14 while the softer,useable food material 46 which is separated from the carcasses during grinding is forced radially outwardly in the grindingchamber 15. The useable and unusable food material are combined within the grindingchamber 15 into a single mass 44 which is forced toward the end of the grindingchamber 15 by theauger 14 until it contacts theorifice plate 18. Theuseable food material 46 is forced through the small openings 19 oforifice plate 18 by the blades of theknife assembly 16 out of the grindingchamber 15.

Theknife assembly 16 also drives the hard,unusable food material 48 into thelarge openings 20 at the center of theorifice plate 18. Rampedentryways 21 on theopenings 20 may assist theunusable material 48 in entering thelarge openings 20 during rotation of theauger 14 andknife assembly 16. Where large pieces of unusable material are larger than theopenings 20, they catch in theopenings 20 and are sheared into smaller pieces by rotation of the knife blades until they are reduced to a size at which they readily pass through thelarge openings 20.

Theuseable food material 46 is partially ground during its travel through the grindingchamber 15 and is further ground as it is driven through the small openings 19 of theorifice plate 18. The openings 19 may open directly to a collection hopper (not shown) positioned beneath theorifice plate 18. In the embodiment illustrated in FIG. 1, after grinding in thechamber 15, the food material mass 44 is slowly pushed into the additional or downstream chamber 17 where it contacts the additional ordownstream knife assembly 32 and some additionaluseable food material 46 is removed from theunusable food material 48 in the mass 44. Theuseable food material 46 is pressed through the additional chambersmall openings 39 in anorifice plate 38, while theunusable food material 48 is forced through thelarger discharge openings 40 into thebone collection cone 24.

The bones and other unusable food material may be assisted in travel through thebone collection cone 24 by abone discharge auger 28 attached to theauger 14 which rotates within thecone 24 anddischarge tube portion 26 thereof. This waste material is then passed into adischarge pipe conduit 29 to a waste disposal area.

The apparatus described above does not form any part of the present invention, but serves primarily to describe the preferred environment in which the present invention is used to obtain an overall reduction in the discharge from the bone collection andelimination apparatus 50. Further details on the structure and operation of this particular apparatus are described in U.S. Pat. No. 5,251,829 assigned to Weiler and Company.

A device for regulating the discharge of the bones from thegrinder 10 is shown generally indicated as 100 in FIG. 1, attached to thebone discharge tube 26 downstream of thebone discharge auger 28. The regulatingdevice 100 comprises anelongated housing 102 adapted for connection to thedischarge tube 26. Thehousing 102 includes aninlet passage 104, anoutlet passage 106 and achamber 108 situated between the inlet and outlet passages. As illustrated in the Figures, theinlet passage 104 is preferably located within thehousing 102 at an angle to theoutlet passage 106 so that thevalve chamber 108 may accommodate areciprocatable valve element 110. Thevalve element 110 is disposed in thechamber 108 along a longitudinal axis of theinlet passage 104. Thehousing 102 may be formed of twointerengaging component parts 102a, 102b which may be separated to facilitate assembly and cleaning of theflow control device 100. Each inlet and outlet may have a projectingrim 129 which defines a point of attachment to the grinding apparatus.

Thevalve element 110 may take the configuration of aplunger element 115 having anelongated valve stem 114 terminating in acylindrical valve head 112. To effect the reciprocating movement necessary for operation, thevalve stem 114 is slidably supported within a slot, or channel 116, formed in the body portion 118 of thehousing 102. Thedevice 100 preferably includes a means for biasing thevalve element 110 into an initial position, and may include any suitable means such as apneumatic cylinder 131, a fluid cylinder or aspring 130.

Turning now to FIGS. 2-4, thevalve head 112 is preferably complementary in configuration to theinlet passage 104, and is shown as anelongated cylinder 120 having afront face 124. The valve head slidably engages theinlet passage 104. Closure of theinlet passage 104 of thedevice 100 is attained when thevalve head 112 extends into theinlet passage 104 such that theexterior surface 113 of thevalve head 112 abuts theinterior surface 105 of theinlet passage 104. In this regard, theinner surface 105 of theinlet passage 104 serves as the "valve seat" of themechanism 100. A preferred material of construction for thehousing 102 andvalve element 112 is stainless steel, and the engagement surfaces of theinlet passage 104 andvalve element 112 may be coated with a thin film of a lubricant approved for food processing apparatus.

In an important aspect of the present invention, thevalve head 112 is specially configured to provide a unique pressureresponsive surface 122 of thevalve head 112 which faces upstream and is in contact with the product flow stream of the grindingapparatus 10. Thispressure surface 122 is the surface which contacts, or confronts, the product flow stream of discharge material in thedischarge tube 26 of the grindingapparatus 10. Rather than having a single, planar valve surface which is oriented perpendicular to the product flow stream as in conventional style valves, thevalve head 112 has apressure surface 122 with multiple facets, or surfaces formed by the cooperation between agroove 128 and front face orpart 124 to define a nonplanar pressure responsive surface in contact with the product flow stream.

Thecylindrical portion 120 of thevalve head 112 hasgroove 128 formed therein which extends downwardly at an angle θ from theupper section 117 of the valve head to thefront face 124 of thevalve element 110. Thegroove 128 is shown in FIGS. 1-4B as being circular in configuration.

Thegroove 128 decreases in depth relative to theexterior surface 113 of thevalve head 112 in a direction rearwardly from thefront face 124 until it intersects theupper section 117 of thevalve head 112. Thecircular groove 128 shown in these Figures may be formed in thevalve head 112 by means of a ball mill. Preferable and especially advantageous results have been obtained from valve elements having valve heads approximately 1.50 inch long and approximately 1.36 inch in diameter, with a groove of approximately 0.75 inch in diameter. Grooves formed invalve heads 112 having an angle θ ranging between approximately 33° and 37° have been found to give desirable results. Typically, the diameter of the groove will correspond to the largest size bone expected to be ejected from thebone collection assembly 50. The angles of the grooves may vary with the size of thevalve head 112 and the stroke of thevalve element 110 within thehousing 102. Alonger valve head 112 would have a longer stroke in and out of theinlet passage 104 and, thus the angle of the groove typically would be less. A valve head having a shorter stroke would require a greater angle.

The operation of theflow control device 100 is shown in FIGS. 2A-B and 3A-B. During operation of thegrinder 10, useable food material is being ground up and passed through thesmaller openings 19, 39 of theorifice plates 18, 38. Meanwhile, the bones and hard portions of the food material are passed out through thelarger openings 20, 40 through thebone collection cone 24 and into thedischarge tube 26 associated therewith.

As this product flow stream encounters the regulatingdevice 100, the backpressure of the grindingapparatus 10 rises. When it reaches a preselected value which approximates the biasing force applied to thevalve element 110 by the biasing means (such asspring 130 or pnuematic cylinder 131), any further increase in backpressure causes movement of thevalve element 110 from its initial, restricted position illustrated in FIG. 2A to an open position as illustrated in FIG. 3A. In the restricted position, thevalve head 112 lies substantially against the valve seat, i.e., theinterior 105 of theinlet passage 104. The apex 132 of thegroove 128 may extend slightly past the edge of the inlet passage so that smaller pieces of bones or hard material may move into thegroove 128 and inch slowly out through thegroove 128. (FIG. 2B.) When large chunks of bony material proceed down thedischarge tube 26 into theinlet 104, the chunks will increase the system backpressure to a point where it exceeds the biasing force onvalve element 110, such that thevalve element 110 moves rearwardly in thehousing 102 against the biasing means 130.

Thegroove 128 defines a restricted passage of variable size, as compared to a valve using a conventional, solid cylindrical plunger element. This groove increases the total surface area of thevalve element 110 which contacts the discharge flow stream, and thus thevalve element 112 of the present invention is more responsive to backpressure conditions which exist within the grindingapparatus 10 than a valve element having a solid, cylindrical head portion.

Large chunks of bones will increase the backpressure of the system and will pass out of theinlet passage 104 into thevalve chamber 108 above thevalve element 110, which is substantially displaced into an open position. The travel of thevalve element 110 in this position is shown in FIGS. 3A and 3B. Once the chunk of discharge material has passed through thegroove 128 out of theinlet passage 104, thevalve element 110 returns to its restricted, closed position.

Thegroove 128 formed in the valve head in effect defines a low volume orifice for the valve. Thegroove 128, in combination with thefront surface 124 of thevalve head 112, allows the pressure of the product flow stream of the grindingapparatus 10 to regulate the discharge of the waste material from the grindingapparatus 10. Thus, the pressureresponsive surface 122 of thevalve element 110 is partially perpendicular to the product flow stream (along front face 124) and largely parallel to the product flow stream (along the groove 128). This special construction allows the pressure of the product flow stream to open and close dependent on the product stream pressure itself, without the need for any external control on the valve to regulate the orifice size. This avoids the need for manual adjustment of the apparatus. The angled face of thevalve element 110 allows thevalve element 112 to place a preselected backpressure on the discharge line, while intermittently "popping" out into an open position to discharge large amounts of material, while still closing very quickly. This backpressure may need to be varied depending upon the type of meat being processed. Adjustment in the backpressure of the device may be easily made by changing the air or fluid pressure or replacing thespring 130 to provide an initial biasing force on thevalve element 110.

It has been found during use of the invention when grinding pork in a grinding apparatus having the construction shown in FIG. 1 and described in U.S. Pat. No. 5,251,829, the discharge from thebone collection assembly 50 has been reduced from 2% by weight down to 0.2% by weight, while still removing bone and foreign objects from the processed food.

An alternative embodiment of avalve element 200 constructed in accordance with the principles of the present invention is illustrated in FIG. 5, wherein thevalve element 200 includes anon-cylindrical valve head 202 mounted on the front of avalve stem 204. Thevalve head 202 has arectangular groove 206 formed therein at an angle, descending from anupper section 208 thereof to thefront 210 of the valve head.

It will be understood that the embodiments of the invention which have been described are merely illustrative of the principles of the present invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.

Claims (31)

We claim:

1. In an apparatus for processing animal carcasses by removing bones and other generally unusable materials from the carcasses while grinding useable food materials from the carcasses, said apparatus having a discharge line for discharging the unusable materials to waste, the improvement comprising,

a flow control assembly for controlling the flow of said materials through said discharge line during operation of said grinding apparatus, the flow control assembly including a valve housing mounted in said discharge line and in communication therewith, the valve housing including a reciprocatable valve element disposed within said housing, said valve element including a head portion which extends into an inlet passage of said valve housing, said flow control assembly including means for biasing said valve element into a first operative position wherein said valve element head portion blocks said inlet passage and contacts flow of discharge material within said discharge line, the valve element head portion having a frontal surface which is responsive to pressure of said material flow within said discharge line, whereby contact between said pressure responsive surface and said discharge material flow in said discharge line results in a movement of said valve member in a direction out of said valve housing and from said first operative position to a second operative position, said second operative position opening said inlet passage to said discharge material flow when said biasing means is overcome by pressure of said discharge material flow, said pressure responsive surface of said valve member being a multifaceted pressure responsive surface, part of said surface being perpendicular to said discharge material flow and part of said surface being non-perpendicular to said discharge material flow.

2. The apparatus of claim 1, wherein said valve element head portion is generally cylindrical and includes a groove extending longitudinally therein at a depth that decreases in downstream direction.

3. The apparatus of claim 2, wherein said valve member has a longitudinal axis, and said groove extends within said valve element head portion at an acute angle from said longitudinal axis.

4. The apparatus of claim 3, wherein said groove has a curved surface and is disposed in said valve element head portion at an angle of between approximately 33° and approximately 37° from said valve member longitudinal axis.

5. The apparatus of claim 2, wherein said groove has a cylindrical surface which extends rearwardly in said valve member head portion from said frontal surface and angularly upwardly such that said groove has a depth which varies along its length.

6. The apparatus of claim 2, wherein said groove defines an opening through said inlet passage when said valve member is in said second operative position, which opening accommodates passage of large pieces of discharge material through said assembly.

7. The apparatus of claim 1, wherein said flow means for biasing said valve element into said first operative position includes a pneumatic cylinder which applies air pressure to said valve element.

8. The apparatus of claim 1, further including an outlet passage disposed in said valve housing at an angle to said inlet passage.

9. The apparatus of claim 1, wherein said valve element is generally rectangular and includes a groove extending longitudinally therein extending between said frontal surface and an upper surface of said valve element.

10. The apparatus of claim 1, wherein said inlet passage of said valve housing is completely open to said material discharge flow when said valve member is in said second operative position.

11. An assembly for regulating the discharge of bones and hard material discharged from a food processing grinding apparatus, the discharge regulating assembly comprising a valve member reciprocatably mounted in a valve housing inserted into a discharge line of said grinding apparatus, the valve housing having an inlet passage and an outlet passage, the valve member being disposed in said valve housing generally between the inlet and outlet passages, said discharge regulating assembly further including means for applying a preselected force to said valve member for biasing it into a closed position wherein a head portion of said valve member is substantially contained within said inlet passage to thereby prevent flow of discharge material out of said grinding apparatus through said valve housing, the valve head having an actuating surface opposing said material being discharged from said grinding apparatus through said discharge line, the actuating surface having multiple components which are responsive to pressure of discharge material in said discharge line, one of said actuating surface components being an elongated groove of variable depth, said actuating surface multiple components cooperating to define a pressure responsive surface of said valve head, whereby, when the pressure of said discharge material in said discharge line exceeds said biasing force, said valve member moves out of said closed position and said groove defines an opening of variable depth in said inlet passage which permits the discharge material out of said discharge line through said housing, said groove depth being dependent upon movement of said valve member out of said closed position.

12. The discharge regulating assembly of claim 11, wherein said head portion is cylindrical.

13. The discharge regulating assembly of claim 12, wherein said groove has a curved surface, said groove having a depth which varies along the length of the groove and said head portion, the depth being greatest at a front face of said valve head portion and least at an upper section of said valve head portion.

14. The discharge regulating assembly of claim 12, wherein said valve head groove has a planar surface.

15. The discharge regulating assembly of claim 11, wherein said groove has a planar surface.

16. The discharge regulating assembly of claim 11, wherein said means for biasing said valve member includes a compression spring.

17. The discharge regulating assembly of claim 11, wherein said means for biasing said valve member includes a pneumatic cylinder.

18. The discharge regulating assembly of claim 11, wherein said pressure responsive surface is a ramped surface.

19. The discharge regulating assembly of claim 11, wherein another component of said pressure responsive surface components includes a surface of said valve head oriented generally perpendicularly to said inlet passage.

20. An apparatus for controlling the flow within a discharge line of unusable material consisting of bones and other hard material discharged from a food grinding apparatus, the flow control apparatus comprising a valve body defining a valve chamber, a valve element mounted within the valve chamber for controlling flow of discharge material between inlet and outlet ports of said valve chamber, the valve element having a head portion adapted for passage in and out of said inlet port, means for applying a biasing force to said valve element to maintain said valve element in a first operative position wherein said valve head position is contained in said inlet port such that flow discharge material through said discharge line into said valve chamber is substantially prevented, valve actuating means responsive to pressure of said discharge material including a pressure responsive surface disposed on said valve element which contacts said discharge material, said pressure responsive surface being oriented both perpendicular and non-perpendicular to flow of discharge material and including a groove longitudinally extending within said valve element head portion and defining a discharge passage through said valve element head portion.

21. The flow control apparatus of claim 20, wherein said valve element head portion groove is an arcuate groove and extends with said head portion at an angle to the longitudinal axis thereof, whereby said groove has a variable depth along its length, said groove depth being greatest at said valve element pressure responsive surface.

22. The flow control apparatus of claim 20, wherein said valve element includes a plunger element, the plunger having a rectangular head portion.

23. The flow control valve of claim 20, wherein said biasing means includes spring means.

24. The flow control apparatus of claim 20, wherein said inlet port is cylindrical, said valve element head portion is cylindrical and said valve element pressure surface groove is arcuate.

25. An apparatus for controlling the flow within a discharge line of an item of food processing equipment, wherein the discharge line conveys a flow of discharge material containing bones and other hard materials, the flow control apparatus comprising a pressure actuatable valve inserted into said discharge line, the valve having a valve body with an inlet passage, an outlet passage and a valve chamber, the inlet passage facing in an upstream direction of said material discharge line, a valve element assembly mounted in the valve chamber, the valve element having a valve head portion mounted on an elongated valve stem portion, the valve element being reciprocatable in said valve body between a first position and a second position, the first position being where said valve head portion extends into said inlet passage and substantially blocks flow of said discharge material through said discharge line into said inlet passage, said valve element being biased into said first position by a biasing means, said valve head portion having a pressure responsive surface opposing said material discharge flow in said material discharge line, said pressure responsive surface having a first portion which is perpendicular to said discharge material flow and a second portion which is non-perpendicular to said discharge material flow, said valve element second position being where said pressure responsive surface non-perpendicular portion is withdrawn from said inlet passage to the extent that an opening is defined in said inlet passage which permits flow of discharge material through said inlet passage.

26. The flow control apparatus of claim 25, wherein said pressure responsive surface non-perpendicular portion includes a groove in said valve element head portion.

27. The flow control apparatus of claim 26, wherein said groove is a curved groove.

28. The flow control apparatus of claim 26, wherein said groove has a depth which varies along the length of said groove and said valve element head portion, the groove depth being greatest at a front face of said head portion and least at an upper surface of said head portion.

29. The flow control apparatus of claim 25, wherein said valve element biasing means includes a pneumatic cylinder.

30. The flow control apparatus of claim 25, wherein said valve element biasing means includes a compression spring.

31. The flow control apparatus of claim 25, wherein said pressure responsive surface non-perpendicular portion includes a ramp extending longitudinally through said valve element head portion.

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